SS Cygni

SS Cygni is a dwarf nova -- a binary star system composed of a normal sunlike-star transferring matter onto a white dwarf companion star. The matter being transferred forms an accretion disk around the white dwarf, and this disk sometimes goes into outburst, becoming hot and bright for a period of several days to a few weeks. Normally these outbursts look similar to one another -- a very fast rise, a plateau of several days, and a steady decline back to quiescence lasting for several weeks -- because the physical causes of these outbursts are the same each time. However, sometimes things go haywire, producing strange looking irregular outbursts. The reasons for these irregular outbursts are not always clear. This series of irregular outbursts occurred in June of 1993, and is one of the strangest cases observed so far in SS Cygni.